A feature of socket wrenches which makes them very easy to use is the one-way ratchet connection between the wrench handle and the socket-receiving stub, so that once a wrench socket is engaged with a bolt head the handle can be turned clockwise to tighten the bolt and turned counterclockwise to start a new stroke without having to disconnect the socket from the bolt head. Socket wrenches, however, have the disadvantage that a different socket is required for each size bolt head.
There are several varieties of adjustable wrenches, but all those applicant has seen must be disengaged from a bolt head and re-engaged on each stroke. This is particularly time-consuming where the location of the bolt to be tightened is such that nearby obstructions limit the length of the wrench stroke and thus necessitate frequent disconnection and reconnection of the wrench with the bolt head. In this respect, adjustable wrenches are similar to spanners, hex wrenches and box wrenches.
The following patents show crescent wrenches which have levers for quick adjustment of the jaw span; but none of them provides a ratchet connection: U.S. Pat. Nos. Sokolov 1,159,428, Shackford 1,434,753, Wettwer 1,452,668, Purdy 1,720,650, Hogstadius 2,587,320 Nordgren 2,970,502, Allegraud 3,232,150 and Miller 4,106,372.
Orr U.S. Pat. No. 3,000,245 discloses a side jaw wrench which has a ratchet action but the mechanism is much more complex and delicate than is that of the present invention.
The principal object of the present invention is to provide an adjustable wrench which may be rotated clockwise to tighten the bolt; and the handle of which may be turned counterclockwise to start a new stroke without disengaging the wrench from the bolt head or returning the bolt to the position that it occupied before the stroke was started.
Another object of the invention is to provide an adjustable wrench which may be quickly opened and closed upon the head of a bolt which is to be tightened.
A further object of the invention is to provide such a wrench in which pressure applied to the wrench while tightening a bolt or nut has no tendency to free the movable wrench jaw.
Still a further object of the invention is to provide such a wrench which is so constructed as to eliminate the possibility of laterally displacing the movable jaw.
Yet another object of the invention is to provide such a wrench in which a tension spring lightly urges the movable jaw toward the fixed jaw, and in which spring tension may be entirely eliminated when desired.
The foregoing objects of the invention are realized by constructing a quickly adjustable ratchet wrench having the following elements:
A quickly adjustable ratchet wrench for rotating objects which have angularly related flat surfaces surrounding an axis of rotation, said wrench being of the type which has a fixed jaw member having a jaw element and a handle, a movable jaw member having a jaw element and an elongated engaging surface, and means mounting said movable jaw member for linear translatory movement on the fixed jaw member between closed and open positions of said jaw elements. A jaw spring lightly biases the movable jaw member toward closed position so that the fixed and movable jaw elements normally close lightly upon an object between them. Locking means including a locking face on the fixed jaw member is selectively engageable with the engaging surface of the movable jaw member to lock the jaw elements closed upon an object between them.
A lever is pivoted on the fixed jaw member on a pivot axis substantially on the line of linear translatory movement of the movable jaw member, and pivotal movement of the lever engages and disengages the engaging surface and the locking face. The lever has a transverse surface which bears on a part of the fixed jaw member when the engaging surface and the locking face are engaged so that manual force applied to the lever is transmitted through the fixed jaw member to rotate an object upon which the jaws are closed, and which pivots away from said part of the fixed jaw member to disengage said engaging surface and locking face and thereby releases the movable jaw member for free linear movement against the bias of the spring; and the lever is so related to the fixed jaw member that a user may manually grip the lever with one hand while leaving the fixed jaw member free, whereby in normal reciprocating action the movable wrench jaw is alternately locked to grip opposite flat surfaces of an object between the jaw elements and released for free rotation of the jaw elements around angles between adjacent flat surfaces of the object without rotating said object.
In a preferred embodiment of the invention, the tension on the spring may be completely released when desired.
In a most preferred embodiment the elongated engaging surface of the movable jaw member is convex so as to include part of the sides of said movable jaw member, and the locking face is concave so as to be engageable with substantially all of said engaging surface.
To simplify the detailed description and claims, the operation of the wrench is described as it is used to tighten a bolt. To loosen or remove a bolt, of course, the position of the wrench on the bolt is reversed so that the working stroke is counterclockwise and the idle stroke is clockwise.
Further, the term "lightly biasing" with reference to the biasing springs is used as a general limitation upon the force with which the movable jaw of the wrench may be biased toward closed position. The biasing force must be small enough that when the lever arm is rotated counter-clockwise to start a new working stroke, the jaws can open sufficiently against the spring bias to slip around the angles of the bolt head instead of loosening the bolt. This, of course, limits the biasing force that can be applied to the movable jaw by the spring.
The engaging surface of the movable jaw member is shown in the drawings as a toothed rack, and the locking face is shown with lugs engaging the rack; and those terms are usually employed hereinafter.
The present device is called a ratchet wrench as a matter of convenience, and not as a precise definition of function; because it does not operate as does a conventional ratchet. When the lever arm is rotated counterclockwise to release the locking lugs from the rack teeth to start a new stroke of the wrench, the locking lugs merely retract from the teeth; and as the jaws spread to go around the angles of the bolt head the rack moves a short distance relative to the locking member. When the jaws again close upon opposite flat sides of the bolt head the rack returns to its original position, and the locking lugs re-engage with the same teeth upon renewed clockwise rotation of the wrench. For practical purposes the wrench may be thought of as a ratchet wrench; but in fact it does not, mechanically, operate as does a ratchet.